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Client does not support authentication protocol requested by server
ExpressionEngine returns the following error: "Client does not support authentication protocol requested by server."
Troubleshooting
Running MySQL v4.1 or newer, the follow error is returned:
Warning: mysql_pconnect(): Client does not support authentication protocol requested by server;
consider upgrading MySQL client
New versions of MySQL use an authentication protocol based on a password hashing algorithm that is incompatible with that used by older (pre-4.1) clients. MySQL can be configured to use the old algorithm, however. The MySQL documentation has more information on the issue.